Correctness¶

Keep bad data out and keep objects consistent when something goes wrong halfway.

Validation

validate_args, check_type and enforce_types: reject bad input with an error that names the parameter.
State safety

revert_on_failure, Transaction and transactional: undo changes when a call fails.

Which one?¶

You want to	Use
Check a business rule (`amount > 0`, not empty)	`validate_args`
Check that an argument is an `int` or `str`	`check_type`
Make your type hints true at runtime	`enforce_types`
Restore an object's attributes if a method fails	`revert_on_failure`
Undo side effects (files, payments) when a step fails	`transactional`